Interstitial keratitis, also known as IK, is an eye condition that affects the cornea. It is a serious condition that can cause blindness if left untreated. Some synonyms for IK include parenchymatous keratitis, idiopathic stromal keratitis, and interstitial corneal inflammation. Other terms that may be used to describe this condition include deep stromal inflammation, keratitis profunda, and chronic relapsing interstitial keratitis. No matter what term is used to describe IK, it is important to seek prompt treatment from a medical professional to minimize the risk of vision loss and other complications.